Umbilical

Abstract

An offshore hydrocarbon-production umbilical having concentrically: an outer sheath, at least two cross-wound armouring layers, and a core enclosed by the armouring layers, and comprising a plurality of elongate active umbilical components, wherein each armouring layer comprises a plurality of reinforced polymer strips. The use of reinforced polymer strips to form the armouring layers achieves a reduced weight but still flexible arrangement, which is significantly easier to manufacture as far fewer strips are required to form the armouring layers compared with the large number of steel wires of conventional armouring layers.

1 . An offshore hydrocarbon-production umbilical comprising concentrically:
 an outer sheath,   at least two cross-wound armouring layers, and   a core enclosed by the armouring layers, and comprising a plurality of elongate active umbilical components,   
       wherein each armouring layer comprises a plurality of reinforced polymer strips, which form a complete annulus around the core as an armouring layer. 
     
     
         2 . An umbilical as claimed in  claim 1  wherein the umbilical has a bending stiffness below 1200 Nm. 
     
     
         3 . An umbilical as claimed in  claim 1  wherein the polymer strips are reinforced by one or more strands of one or more high strength organic yarns having a tensile modulus >70 GPa. 
     
     
         4 . An umbilical as claimed in  claim 3  wherein the high strength organic yarns comprise fibres comprising one or more of the group comprising; aromatic polyamide (aramid) fibre, aromatic polyester fibre, liquid crystal fibre, high performance polyethylene fibre, and aromatic heterocyclic polymer fibre (PBO), or a combination thereof. 
     
     
         5 . An umbilical as claimed in  claim 4  wherein the high strength organic fibres comprise aromatic heterocyclic polymer fibre (PBO). 
     
     
         6 . An umbilical as claimed in  claim 1  wherein each reinforced polymer strip comprises at least two strands, optionally at least 4-20 strands, and preferably in the range of 4-12 strands. 
     
     
         7 . An umbilical as claimed in  claim 6  wherein each reinforced polymer strip comprises 6, 7, 8, 9 or 10 strands. 
     
     
         8 . An umbilical as claimed in  claim 1  wherein each armouring layer comprises between 5-25 reinforced polymer strips, optionally between 8-20 or between 9-18 reinforced polymer strips. 
     
     
         9 . An umbilical as claimed in  claim 1  wherein the reinforced polymer strips have a thickness in the range 1 mm to 5 mm, and a width in the range 10 mm to 50 mm. 
     
     
         10 . An umbilical as claimed in  claim 1  wherein the reinforced polymer strips have a tensile load capacity in the range 1300 N to 20,000 N. 
     
     
         11 . An umbilical as claimed in  claim 1  wherein the reinforced polymer strips are wound in a helical pattern. 
     
     
         12 . An umbilical as claimed in  claim 1  wherein the umbilical is a thermoplastic, hybrid, HFL, IWOCS or power cable, preferably an IWOCS umbilical. 
     
     
         13 . An umbilical as claimed in  claim 1  for use at a depth of greater than 2000 m. 
     
     
         14 . An IWOCS umbilical comprising consecutively:
 an outer sheath,   at least two cross-wound armouring layers, and   a core enclosed by the armouring layers, and comprising a plurality of elongate active umbilical components,   
       wherein each armouring layer comprises a plurality of reinforced polymer strips as defined in  claim 1  in the form of a complete annulus around the core. 
     
     
         15 . A method of manufacturing an offshore umbilical as defined in  claim 1  comprising at least the steps of:
 (i) providing a core of comprising a plurality of elongate active umbilical components; 
 (ii) winding at least two armouring layers as defined in  claim 1  around the core to form a complete annulus around the core; and 
 (iii) providing an oversheath.